In aerospace applications, it is generally desirable to minimize the weight of all components on an aircraft. Less weight translates into reduced fuel consumption and lower operating costs. Two commonly used position sensors for aerospace applications are the linear variable differential transformer (LVDT) and the rotary variable differentiable transformer (RVDT). These types of sensors are used in aerospace applications particularly due to their ability to perform under harsh environmental conditions with high reliability and accuracy. However, conventional LVDT and RVDT sensors may have four to six interfacing wires per sensor. These sensors typically use five wires at the electrical interface for excitation of the primary coil and outputs from the secondary coils. When a large number of these sensors are used for the purpose of providing redundancy, the number and length of the wires connecting the signals to the electronics tend to complicate the system wiring and increase the overall weight. They also increase the likelihood of a break in one of the wires at the terminations within the transducer.
Further, when employing these sensors, the user must consider the best means for correcting variation in output data due to variations in temperature. The transducer output at a fixed position of the moving member changes when the operating temperature increases or decreases from standard room temperature. This is because the resistivity of copper of which the coil wires are made is a function of temperature, and this affects the transducer output voltage. Moreover, the change in the transducer output with temperature is also dependent on the position of the moving member. Thus the transducer output is a nonlinear two dimensional function of position and temperature.
The user must also consider the best means for correcting variation in output data due to the nonlinearity of the transducer output with respect to the position of the moving member.
Embodiments of the invention represent an advancement over the state of the art with respect to position sensors used in aerospace applications. These are described briefly below.